German-language esoteric writing is dominated by two bodies of material. The first is Guido von List's Armanen runic system, an eighteen-rune reinterpretation of the historical Younger Futhark published in German in 1906 and 1908, which became influential within twentieth century occultism and, more troublingly, within volkisch and Nazi-era esoteric ideology. List claimed the eighteen runes and their threefold interpretive method were revealed to him during an eleven-month period of blindness following cataract surgery, a personal account that later occultist readers and, separately, nationalist readers treated very differently from one another in the decades after his death in 1919.
The second is the German terminology of Paracelsian elemental and alchemical thought: the names given to the elemental spirits, sylphs, undines, salamanders and gnomes, and the alchemical tria prima of sulphur, mercury and salt as those concepts were discussed and transmitted in German rather than in Latin.
Earlier German Rosicrucian and mystical writing, including that of Jakob Bohme, belongs with them. What the three have in common is that the German is the original and not a rendering, so a disagreement over a term is a disagreement about what an author wrote rather than about what a translator chose. That is a different kind of argument, and a more settleable one.